Multi-tine cutting device

ABSTRACT

A cutting device is provided that includes an outer tube. The outer tube includes an inner surface defining a passageway. An inner tube is movably disposed in the passageway such that a distal end of the inner tube extends beyond a distal end of the outer tube. The distal end of the inner tube includes a first cutting element. An inner surface of the inner tube defines a lumen. A shaft is slidably disposed in the lumen. The shaft has a distal end including a second cutting element. A deployment mechanism is coupled to a proximal end of the outer tube. The deployment mechanism includes a body, a push button disposed within the body and a collar disposed about the body. The shaft is fixed relative to the collar and the inner tube is fixed relative to the push button. Systems and methods are disclosed.

The present application is a divisional of U.S. application Ser. No.14/288,508, filed May 28, 2014; all of which is incorporated herein byreference.

TECHNICAL FIELD

The present disclosure generally relates to medical devices to dissectand evacuate tissue, and more particularly to a surgical system andmethod employing a retractable device for treatment of hypertrophiedligamentum flavum.

BACKGROUND

Spinal stenosis typically occurs when the spinal cord, cauda equinaand/or nerve root(s) are impinged by one or more tissues in the spine,such as a buckled or thickened ligamentum flavum. Impingement of neuraland/or neurovascular tissue in the spine by a buckled or thickenedligamentum flavum may cause pain, numbness and/or loss of strength ormobility in one or both of a patient's lower limbs and/or of thepatient's back.

In lumbar spinal stenosis (LSS), the space around the spinal cordbecomes narrow, thus compressing the spinal cord and the nerve roots.This causes back pain with neurogenic claudication, i.e., pain,numbness, or weakness in the legs that worsens with standing or walkingand is alleviated with sitting or leaning forward. Compression of neuralelements generally occurs as a result of hypertrophied facet orligamentum flavum hypertrophy. LSS is one of the most common reasons forback surgery and the most common reason for lumbar spine surgery inadults over 65 years of age. Patients suffering from spinal stenosis aretypically first treated with conservative approaches such as exercisetherapy, analgesics, anti-inflammatory medications, and epidural steroidinjections. When these conservative treatment options fail and symptomsare severe, surgery may be required to remove impinging tissue anddecompress the impinged nerve tissue.

The source of most cases of lumbar spinal stenosis is thickening of theligamentum flavum. Spinal stenosis may also be caused by subluxation,facet joint hypertrophy, osteophyte formation, underdevelopment ofspinal canal, spondylosis deformans, degenerative intervertebral discs,degenerative spondylolisthesis, degenerative arthritis, ossification ofthe vertebral accessory ligaments and the like. A less common cause ofspinal stenosis, which usually affects patients with morbid obesity orpatients on oral corticosteroids, is excess fat in the epidural space.The excessive epidural fat compresses the dural sac, nerve roots andblood vessels contained therein and resulting in back and leg pain andweakness and numbness of the legs. Spinal stenosis may also affect thecervical and, less commonly, the thoracic spine.

Patients suffering from spinal stenosis are typically first treated withexercise therapy, analgesics and anti-inflammatory medications. Theseconservative treatment options frequently fail. If symptoms are severe,surgery is required to decompress the canal and nerve roots.

To correct stenosis in the lumbar region, an incision is made in theback and the muscles and supporting structures are stripped away fromthe spine, exposing the posterior aspect of the vertebral column. Thethickened ligamentum flavum is then exposed by removal of the bony arch(lamina) covering the back of the spinal canal (laminectomy). Thethickened ligament can then be excised with sharp dissection with ascalpel or punching instruments such as a Kerison punch that is used toremove small chips of tissue. The procedure is performed under generalanesthesia. Patients are usually admitted to the hospital forapproximately five to seven days depending on the age and overallcondition of the patient. Patients usually require between six weeks andthree months to recover from the procedure. Many patients need extendedtherapy at a rehabilitation facility to regain enough mobility to liveindependently.

Much of the pain and disability after an open laminectomy is due to thetearing and cutting of the back muscles, blood vessels and supportingligaments and nerves that occurs during the exposure of the spinalcolumn. Also, because these spine stabilizing back muscles and ligamentsare stripped and cut off, the spine these patients frequently developspinal instability post-operatively.

Minimally invasive techniques result in less post-operative pain andfaster recovery compared to traditional open surgery. Percutaneousinterventional spinal procedures can be performed with local anesthesia,thereby sparing the patient the risks and recovery time required withgeneral anesthesia. Another advantage is that there is less damage tothe paraspinal muscles and ligaments with minimally invasive techniquesreducing pain and preserving these important stabilizing structures.

Various techniques for minimally invasive treatment of the spine areknown. Microdiscectomy is performed by making a small incision in theskin and deep tissues to create a portal to the spine. A microscope isthen used to aid in the dissection of the adjacent structures prior todiscectomy. The recovery period for this procedure is much shorter thantraditional open discectomies. Percutaneous discectomy devices withfluoroscopic guidance have been used successfully to treat disorders ofthe disc, but not to treat spinal stenosis or the ligamentum flavumdirectly. Arthroscopy or direct visualization of the spinal structuresusing a catheter or optical system have also been proposed to treatdisorders of the spine, including spinal stenosis. However, thesedevices still use miniaturized standard surgical instruments and directvisualization of the spine, similar to open surgical procedures. Thesedevices and techniques are limited by the small size of the canal andthese operations are difficult to perform and master. Also, theseprocedures are painful and often require general anesthesia. Thearthroscopy procedures are time consuming and the fiber optic systemsare expensive to purchase and maintain. In addition, because the nervesof the spine pass through the core of the spine directly in front of theligamentum flavum, any surgery, regardless of whether is open orpercutaneous, includes a risk of damage to those nerves.

It is desirable to provide a method and device for treating spinalstenosis and other spinal disorders without requiring open surgery. Itis further desired to provide a system that protects the thecal sac ordura containing the spinal nerves while the ligamentum flavum is cut.Accordingly, there is a need for devices and methods to provideefficient severing or cutting of tissue that can be used during aminimally invasive procedure and/or during an open surgical procedure,such as, for example, open decompression.

SUMMARY

In one embodiment, in accordance with the principle so the presentdisclosure, a cutting device includes an outer tube extending along alongitudinal axis between a proximal end and a distal end. The outertube comprises an inner surface defining a passageway. An inner tube isrotatably disposed in the passageway such that a distal end of the innertube extends beyond the distal end of the outer tube. The distal end ofthe inner tube comprises a first cutting element. An inner surface ofthe inner tube defines a lumen. A shaft is slidably disposed in thelumen. The shaft comprises a distal end including a second cuttingelement. A deployment mechanism is coupled to the proximal end of theouter tube. The deployment mechanism comprises a body, a push buttondisposed within the body and a collar disposed about the body. The shaftis fixed relative to the collar and the inner tube is fixed relative tothe push button.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will become more readily apparent from thespecific description accompanied by the following drawings, in which:

FIG. 1 is a side view, in part phantom, of components of a surgicalsystem in accordance with the principles of the present disclosure;

FIG. 2 is a side, cross sectional view of components shown in FIG. 1;

FIG. 3 is a side, cross sectional view of components shown in FIG. 1;

FIG. 4 is a side, cross sectional view of components shown in FIG. 1;

FIG. 5 is a side view of components shown in FIG. 1, with partsseparated;

FIG. 6 is perspective view of a component shown in FIG. 1;

FIG. 7 is a side, cross sectional view of a component shown in FIG. 1;

FIG. 8 is an end view of a component shown in FIG. 1;

FIG. 9 is a perspective view of a component shown in FIG. 1;

FIG. 10 is a side view of a component shown in FIG. 1;

FIG. 11 is a side, cross sectional view of a component shown in FIG. 1;

FIG. 12 is a top, cross sectional view of a component shown in FIG. 1;

FIG. 13 is perspective view of a component shown in FIG. 1;

FIG. 14 is a side, cross sectional view of a component shown in FIG. 1;

FIG. 15 is a perspective view of a component shown in FIG. 1;

FIG. 16 is a cross sectional view of a component shown in FIG. 1;

FIG. 17 is a perspective view of a component shown in FIG. 1;

FIG. 17A is perspective view of a component shown in FIG. 1;

FIG. 18 is an end view of a component shown in FIG. 1;

FIG. 19 is a cross sectional view of a component shown in FIG. 1 takenalong lines A-A in FIG. 18;

FIG. 20 is a side view of a component shown in FIG. 1;

FIG. 21 is a cross sectional view of a component shown in FIG. 1 takenalong lines B-B in FIG. 20;

FIG. 22 is a side view of a component shown in FIG. 1;

FIG. 23 is a cross sectional view of a component shown in FIG. 1 takenalong lines C-C in FIG. 22;

FIG. 24 is an end view of a component shown in FIG. 1;

FIG. 25 is a side view of a component shown in FIG. 1;

FIG. 26 is perspective view of a component shown in FIG. 1;

FIG. 27 is an end, cross sectional view of a component shown in FIG. 1;

FIG. 28 is perspective view of a component shown in FIG. 1; and

FIG. 29 is perspective view of a component shown in FIG. 1.

Like reference numerals indicate similar parts throughout the figures.

DETAILED DESCRIPTION

The exemplary embodiments of a surgical system 30 and related methods ofuse disclosed are discussed in terms of medical devices for thetreatment of musculoskeletal disorders, and more particularly, in termsof a surgical system and method for cutting through soft tissues.

Devices for efficient severing or cutting of a material or substancesuch as nerve and/or soft tissue suitable for use in open surgicaland/or minimally invasive procedures are disclosed. The followingdescription is presented to enable any person skilled in the art to makeand use the present disclosure. Descriptions of specific embodiments andapplications are provided only as examples and various modificationswill be readily apparent to those skilled in the art.

Lumbar spinal stenosis (LSS) may occur from hypertrophied bone orligamentum flavum, or from a ligamentum flavum that collapses into thespinal canal. LSS can present clinical symptoms such as leg pain andreduced function. Conventional treatments include epidural steroidinjections, laminotomy, and laminectomy. Surgical interventions whichremove at least some portion of the lamina are usually performed througha relatively large incision, and may result in spinal instability fromremoval of a large portion of the lamina. Consequently, a percutaneousapproach which removes just enough tissue (lamina or ligamentum flavum)to be effective is provided.

In one embodiment, a device having a retractable ballpoint pen-likemechanism is provided to dissect and evacuate the hypertrophiedligamentum flavum in Lumbar Spinal Stenosis. In one embodiment, thedevice includes an anchor hook. The anchor hook is a central hook toanchor and pull on ligamentum flavum (LF) to increase a potentialepidural space. In one embodiment, a suture anchor mechanism can also beutilized. The anchor hook evacuates the dissected LF tissue into abarrel or cannula. An orbiting hook is deployed a distance not furtherthan anchor hook. The orbiting hook is deployed with a deploymentmechanism similar to that of a retractable ballpoint pen-like mechanism.An atraumatic tip of the orbiting hook will pass through the ligamentumflavum. An inner cutting edge of the orbiting hook will cut throughligamentum flavum fibers as the inner cutting edge retracts into thebarrel. 6 to 20 consecutive deployments of the orbiting hook may berequired to dissect the ligamentum flavum by making an annular cut. Uponcompletion of the annular cut, the anchor hook will evacuate thedissected ligamentum flavum into the barrel.

It is contemplated that one or all of the components of the surgicalsystem may be disposable, peel-pack, pre-packed sterile devices. One orall of the components of the surgical system may be reusable. Thesurgical system may be configured as a kit with multiple sized andconfigured components, such as, for example, hooks and/or tines that arepreformed to have different sizes and shapes.

The present disclosure may also be alternatively employed withprocedures for treating the muscles, ligaments, tendons or any otherbody part. The system and methods of the present disclosure may also beused on animals, bone models and other non-living substrates, such as,for example, in training, testing and demonstration.

The present disclosure may be understood more readily by reference tothe following detailed description of the disclosure taken in connectionwith the accompanying drawing figures, which form a part of thisdisclosure. It is to be understood that this disclosure is not limitedto the specific devices, methods, conditions or parameters describedand/or shown herein, and that the terminology used herein is for thepurpose of describing particular embodiments by way of example only andis not intended to be limiting of the claimed disclosure. Also, as usedin the specification and including the appended claims, the singularforms “a,” “an,” and “the” include the plural, and reference to aparticular numerical value includes at least that particular value,unless the context clearly dictates otherwise. Ranges may be expressedherein as from “about” or “approximately” one particular value and/or to“about” or “approximately” another particular value. When such a rangeis expressed, another embodiment includes from the one particular valueand/or to the other particular value. Similarly, when values areexpressed as approximations, by use of the antecedent “about,” it willbe understood that the particular value forms another embodiment. It isalso understood that all spatial references, such as, for example,horizontal, vertical, top, upper, lower, bottom, left and right, are forillustrative purposes only and can be varied within the scope of thedisclosure. For example, the references “upper” and “lower” are relativeand used only in the context to the other, and are not necessarily“superior” and “inferior”.

Further, as used in the specification and including the appended claims,“treating” or “treatment” of a disease or condition refers to performinga procedure that may include administering one or more drugs to apatient (human, normal or otherwise or other mammal), in an effort toalleviate signs or symptoms of the disease or condition. Alleviation canoccur prior to signs or symptoms of the disease or condition appearing,as well as after their appearance. Thus, treating or treatment includespreventing or prevention of disease or undesirable condition (e.g.,preventing the disease from occurring in a patient, who may bepredisposed to the disease but has not yet been diagnosed as having it).In addition, treating or treatment does not require complete alleviationof signs or symptoms, does not require a cure, and specifically includesprocedures that have only a marginal effect on the patient. Treatmentcan include inhibiting the disease, e.g., arresting its development, orrelieving the disease, e.g., causing regression of the disease. Forexample, treatment can include reducing acute or chronic inflammation;alleviating pain and mitigating and inducing re-growth of new ligament,bone and other tissues; as an adjunct in surgery; and/or any repairprocedure. Also, as used in the specification and including the appendedclaims, the term “tissue” includes soft tissue, ligaments, tendons,cartilage and/or bone unless specifically referred to otherwise.

The components of system 30 can be fabricated from biologicallyacceptable materials suitable for medical applications, includingmetals, synthetic polymers, ceramics and bone material and/or theircomposites, depending on the particular application and/or preference ofa medical practitioner. For example, the components of system 30,individually or collectively, can be fabricated from materials such asstainless steel alloys, commercially pure titanium, titanium alloys,Grade 5 titanium, super-elastic titanium alloys, cobalt-chrome alloys,stainless steel alloys, superelastic metallic alloys (e.g., Nitinol,super elasto-plastic metals, such as GUM METAL™ manufactured by ToyotaMaterial Incorporated of Japan), ceramics and composites thereof such ascalcium phosphate (e.g., SKELITE™ manufactured by Biologix Inc.),thermoplastics such as polyaryletherketone (PAEK) includingpolyetheretherketone (PEEK), polyetherketoneketone (PEKK) andpolyetherketone (PEK), carbon-PEEK composites, PEEK-BaSO.sub.4 polymericrubbers, polyethylene terephthalate (PET), fabric, silicone,polyurethane, silicone-polyurethane copolymers, polymeric rubbers,polyolefin rubbers, hydrogels, semi-rigid and rigid materials,elastomers, rubbers, thermoplastic elastomers, thermoset elastomers,elastomeric composites, rigid polymers including polyphenylene,polyamide, polyimide, polyetherimide, polyethylene, epoxy, bone materialincluding autograft, allograft, xenograft or transgenic cortical and/orcorticocancellous bone, and tissue growth or differentiation factors,partially resorbable materials, such as, for example, composites ofmetals and calcium-based ceramics, composites of PEEK and calcium basedceramics, composites of PEEK with resorbable polymers, totallyresorbable materials, such as, for example, calcium based ceramics suchas calcium phosphate, tri-calcium phosphate (TCP), hydroxyapatite(HA)-TCP, calcium sulfate, or other resorbable polymers such aspolyaetide, polyglycolide, polytyrosine carbonate, polycaroplaetohe andtheir combinations. Various components of system 30 may have materialcomposites, including the above materials, to achieve various desiredcharacteristics such as strength, rigidity, elasticity, compliance,biomechanical performance, durability and radiolucency or imagingpreference.

The components of system 30, individually or collectively, may also befabricated from a heterogeneous material such as a combination of two ormore of the above-described materials. The components of system 30 maybe monolithically formed, integrally connected or include fasteningelements and/or instruments, as described herein.

The following discussion includes a description of a system forperforming a surgical procedure and related methods of employing thesystem in accordance with the principles of the present disclosure.Alternate embodiments are also disclosed. Reference will now be made indetail to the exemplary embodiments of the present disclosure, which areillustrated in the accompanying figures. Turning now to FIGS. 1-28,there are illustrated components of the system for performing a surgicalprocedure in accordance with the principles of the present disclosure.

System 30 includes a surgical instrument, such as, for example amulti-tine cutting device 32. Device 32 comprises an extension tube,such as, for example, an outer tube 34 extending along a longitudinalaxis D between a proximal end 36 and a distal end 38. Tube 34 comprisesan inner surface 40 defining a passageway 42 having a cylindrical crosssectional configuration and a uniform width along the entire length oftube 34, as shown in FIG. 6, for example. Ends 36, 38 each include anopening that is in communication with passageway 42 such that an itemmay be inserted into the opening in end 36, translate along axis Dthrough passageway and exit tube 34 through the opening in end 38. Insome embodiments, passageway 42 may have various cross sectionconfigurations, such as, for example, oval, oblong, triangular,rectangular, square, polygonal, irregular, uniform, non-uniform,variable, tubular and/or tapered. In some embodiments, tube 34 comprisesa flexible material configured to allow tube 34 to bend at leastslightly without breaking. In some embodiments, tube 34 comprises arigid material that prevents tube 34 from bending without breaking.

Device 32 comprises an inner tube 44 disposed in passageway 42 such thata distal end 46 of tube 44 extends beyond end 38 for positioning outsideof passageway 42. Tube 44 is movably disposed in passageway 42 such thattube 44 is rotatable within passageway 42 about axis D and istranslatable within passageway 42 along axis D. End 46 is defined by acutting element 48, best shown in FIGS. 7-12. Cutting element 48comprises a plurality of tines 50 that are spaced apart from oneanother. In some embodiments, cutting element 48 is offset from alongitudinal axis defined by tube 44 such that cutting element 48 isoffset from axis D when tube 44 is positioned within passageway 42. Tube44 comprises an inner surface 52 defining a lumen 54 having acylindrical cross sectional configuration that is coaxial with thelongitudinal axis defined by tube 44 such that lumen 54 is coaxial withpassageway 42 when tube 44 is disposed within passageway 42. In someembodiments, lumen may have various cross section configurations, suchas, for example, oval, oblong, triangular, rectangular, square,polygonal, irregular, uniform, non-uniform, variable, tubular and/ortapered.

In some embodiments, cutting element 48 is integrally and/ormonolithically formed with tube 44. In some embodiments, tube 44includes an inner surface 56 defining a cavity 58 having a shaft 60 ofcutting element 48 positioned therein such that shaft 60 is fixedrelative to tube 44. Cavity 58 has a cylindrical cross sectionalconfiguration. Shaft 60 extends parallel to axis D. Shaft 60 is offsetfrom axis D when tube 44 is positioned within passageway 42. In someembodiments, shaft 60 can be variously connected with cavity 48, suchas, for example, monolithic, integral connection, frictional engagement,threaded engagement, mutual grooves, screws, adhesive, nails, barbsand/or raised element. In some embodiments, shaft 60 is removablypositioned in cavity 48 and system 30 comprises a plurality of cuttingelements 48 each having a different configuration such that a selectedcutting element 48 may be positioned within cavity 48. For example,system 30 may include a plurality of cutting elements 48 each having adifferent number of tines, a different maximum width, etc. In someembodiments, cavity 58 may have various cross section configurations,such as, for example, oval, oblong, triangular, rectangular, square,polygonal, irregular, uniform, non-uniform, variable, tubular and/ortapered.

In some embodiments, tines 50 are disposed radially about a stylet 62such that tines 50 define a tine arrangement. In some embodiments, tines50 are evenly spaced apart from one another. In some embodiments,cutting element 48 includes six tines 50 that are spaced apart from oneanother at a 60 degree angle. In some embodiments, cutting element 48includes eight tines 50 that are spaced apart from one another at a 45degree angle. In some embodiments, tines 46 are disposed about stylet 62in a non-uniform manner such that one set of adjacent tines 50 arespaced apart an angle that is different from an angle in which anotherset of adjacent tines 50 are spaced apart. In some embodiments, a distalend 64 of stylet 62 protrudes distally from a center of the tinearrangement, as shown in FIGS. 9 and 11, for example. In someembodiments, end 64 comprises a sharp and/or pointed tip configured topenetrate tissue. In some embodiments, end 64 comprises a planar orblunt tip configured to engage tissue, without penetrating tissue. Insome embodiments, cutting element 48 may include two or more tines 50.In some embodiments, each of tines 50 is identical. In some embodiments,at least one of tines 50 has a different size or shape than at least oneof the other tines 50. In some embodiments, tines 50 are each made of ametal alloy, such as, for example, nitinol. In some embodiments, tines50 are formed entirely from nitinol.

In some embodiments, as shown in FIG. 11, for example, tines 50 eachinclude a portion 66 that extends parallel to axis D and/or shaft 60 andan arcuate portion 68 extending transverse to axis D and/or shaft 60having a continuous radius of curvature. End surfaces 70 of portions 68face away from end 64. Inner surfaces of each tine 50 engage an outersurface of stylet 62 to couple tines 50 with stylet 62, as shown in FIG.11. Shaft 60 is positioned over portions 66 such that an inner surfaceof shaft 60 engages outer surfaces of tines 50 to position portions 66between shaft 60 and stylet 62 to fix tines 50 relative to stylet 62. Insome embodiments, tines 50 can be variously connected with stylet 62,such as, for example, monolithic, integral connection, frictionalengagement, threaded engagement, mutual grooves, screws, adhesive,nails, barbs and/or raised element.

A stationary rod, such as, for example, shaft 72 is slidably disposed inlumen 54. Shaft 72 comprises a threaded proximal end 74 and a distal end76 comprising an inner surface 78 defining an aperture 80 having acylindrical cross sectional configuration, as shown in FIGS. 13 and 14.A shaft 82 of a cutting element 84 is disposed in aperture 80 such thatshaft 82 is fixed relative to aperture 80. Cutting element 84 includes asingle hook 86. In some embodiments, shaft 82 can be variously connectedwith aperture 80, such as, for example, monolithic, integral connection,frictional engagement, threaded engagement, mutual grooves, screws,adhesive, nails, barbs and/or raised element. In some embodiments, shaft82 is removably positioned in aperture 80 and system 30 comprises aplurality of cutting elements 84 each having a different configurationsuch that a selected cutting element 84 may be positioned in aperture80. For example, system 30 may include a plurality of cutting elements84 each having a different number of hooks, different size hooks, adifferent maximum width, etc. In some embodiments, aperture 80 may havevarious cross section configurations, such as, for example, oval,oblong, triangular, rectangular, square, polygonal, irregular, uniform,non-uniform, variable, tubular and/or tapered.

Device 32 comprises a deployment mechanism 88 coupled to end 36.Mechanism 88 comprises a body 90 including a retainer nut, such as, forexample, a portion 92 and a stationary spline, such as, for example, aportion 94 that is removable from portion 92. Portion 92 comprises athreaded proximal end 96 and an inner surface defining a seat recess 100and a throughhole 102 distal to seat recess 100, as shown in FIGS. 15and 16. Tube 34 extends through throughhole 102. In some embodiments, anouter surface of tube 34 engages surface 98 to fix tube 34 relative toportion 92.

Portion 94 comprises a proximal end 104 having a first diameter and adistal end 106 having a second diameter that is greater than the firstdiameter, as shown in FIGS. 17-21. An interface between ends 104, 106defines a ledge 108. An inner surface 110 of portion 94 comprises aninternal thread form 112 at end 106. Surface 110 comprises a pluralityof spaced apart grooves 114 positioned between ends 104, 106. Grooves114 each extend parallel to a longitudinal axis defined by portion 94.Thread form 112 engages threads on end 96 to couple portion 92 withportion 94, as shown in FIGS. 1-3. Surface 110 defines a conduit 116.Portion 94 comprises openings at ends 104, 106 that are in communicationwith conduit 116 such that an item may be passed through the opening inend 104, through conduit 116, into portion 92 and exit portion 92through throughhole 102. In some embodiments, grooves 114 each have thesame length to prevent locking of tube 44 relative to body 90 and/orshaft 72 relative to body 90.

In some embodiments, portion 94 comprises one or a plurality of holes105 extending through inner and outer surfaces of end 104 in a directionthat is perpendicular to a longitudinal axis defined by portion 94.Holes 105 each have a cylindrical cross sectional configuration. Holes105 each have a pin, such as, for example, a rod 125 disposed therein.Rod 125 comprises an end 127 configured for disposal in one of holes 105and an opposite end 129, as shown in FIG. 17A. In some embodiments, end129 comprises a tool engagement feature 131 configured for engagementwith a tool, such as, for example, a driver and/or actuator to rotaterod 125 about a longitudinal axis defined by rod 125. In someembodiments, end 127 comprises an external thread form configured toengage an internal form of hole 105 to fix rod 125 relative to portion94. In some embodiments, rods 125 can be variously connected withportion 94, such as, for example, monolithic, integral connection,frictional engagement, threaded engagement, mutual grooves, screws,adhesive, nails, barbs and/or raised element. In some embodiments,portion 94 comprises a pair of holes 105 that are disposed opposite oneanother such that holes 105 are aligned and/or coaxial, as shown in FIG.21. In some embodiments, portion 94 comprises a plurality of holes 105disposed radially about portion 94. Portion 94 further comprises a slot115 extending parallel to a longitudinal axis defined by portion 94.Slot 115 has a width or diameter greater than that of end 129 such thatend 129 can translate within slot 115. Slot 115 includes an arcuate endconfigured to accommodate the arcuate cross sectional configuration ofend 129.

An actuator cutter, such as, for example, an actuator 118 is movablydisposed in conduit 116. Actuator 118 comprises a portion 118 a and aportion 118 b, as shown in FIGS. 22-25. Portion 118 b is fixed relativeto portion 118 a. In some embodiments, portion 118 b is integrallyand/or monolithically formed with portion 118 a. Portion 118 b has adiameter that is greater than that of portion 118 a. Portion 118 acomprises an inner surface 120 defining a channel 122 that is coaxialwith axis D. A proximal end of tube 44 is disposed channel 122 such thatan outer surface of tube 44 engages surface 120 to fix tube 44 relativeto actuator 118. Portion 118 b comprises an inner surface 124 defining achamber 126 having a compression spring, such as, for example, spring128 disposed therein such that a proximal end 130 of spring 128 engagessurface 124 and a distal end 132 of spring 128 is disposed in seatrecess 100. This configuration biases actuator 118 in the directionshown by arrow E within body 90. A proximal end of portion 118 bcomprises a plurality of angled teeth 134. Portion 118 b comprises aplurality of concavely curved cutouts 136 positioned between adjacentteeth 134. In some embodiments, cutouts 136 are continuously curved. Anouter surface of portion 118 b comprises a plurality of spaced apartridges 138 configured for disposal in grooves 114, as will be discussed.Ridges 138 are disposed radially about portion 118 b. In someembodiments, ridges 138 are evenly spaced apart from one another. Insome embodiments, proximal ends of ridges 138 are angled to facilitateinsertion and/or removal of ridges 138 with grooves 114. In someembodiments, tube 44 can be variously connected with actuator 118, suchas, for example, monolithic, integral connection, frictional engagement,threaded engagement, mutual grooves, screws, adhesive, nails, barbsand/or raised element.

A plug cutter push button, such as, for example, a push button 140comprises an end 142 extending outside of conduit 116 and an end 144disposed within conduit 116. End 144 comprises a plurality of angledteeth 146 configured to mate with teeth 134. End 144 comprises aplurality of concavely curved cutouts 148 positioned between adjacentteeth 146, as shown in FIG. 26. In some embodiments, cutouts 148 arecontinuously curved. An outer surface of push button 140 comprises aplurality of spaced apart ridges 150 disposed in grooves 114 to allowridges 150 to translate within grooves in the direction shown by arrow Eor the direction shown by arrow F. Ridges 150 are positioned radiallyabout push button 140. In some embodiments, ridges 150 are evenly spacedapart from one another. In some embodiments, ridges 150 have arectangular or square configuration. In some embodiments, ridges 150 areeach aligned with one of teeth 146. In some embodiments, device 32includes the same number of ridges 138 and ridges 150. In someembodiments, device 32 includes the same number of ridges 138, ridges150 and grooves 114. Push button 140 comprises a slot 152 having anoblong configuration extending parallel to a longitudinal axis definedby push button 140 extending through inner and outer surfaces of pushbutton 140. In some embodiments, slot 152 can have various shapeconfigurations, such as, for example, oval, oblong, polygonal,irregular, uniform, non-uniform, variable and/or tapered. An innersurface of push button 140 defines a channel 154 having a cylindricalcross sectional configuration. An outer surface of actuator 118 engagesthe inner surface of push button 140 to fix actuator 118 relative topush button 140. Because tube 44 is fixed relative to actuator 118 anactuator is fixed relative to push button 140, tube 44 is axially fixedrelative to push button 140 such that moving push button 140 along axisD in the direction shown by arrow E or the direction shown by arrow Falso moves tube 44 in the direction shown by arrow E or the directionshown by arrow F. In some embodiments, actuator 118 can be variouslyconnected with push button 140, such as, for example, monolithic,integral connection, frictional engagement, threaded engagement, mutualgrooves, screws, adhesive, nails, barbs and/or raised element.

An anchor hook guide, such as, for example, a substantially disc-shapedguide member 156 is movably disposed in channel 154. Guide member 156comprises an inner surface defining a central threaded blind hole 158extending into a lower surface 160 of guide member 156, as shown in FIG.28. Hole 158 comprises an internal thread form 162 configured to engagethe external thread form on end 74 to fix shaft 72 relative to guidemember 156, as shown in FIGS. 2 and 3. Guide member 156 comprises anarcuate outer surface 164 extending between surface 160 and an uppersurface 166. Surface 164 is configured to slidingly engage the innersurface of push button 140 that defines channel 154 such that guidemember 156 can translate axially within channel 154 in the directionshown by arrow E and the direction shown by arrow F. Surfaces 160, 166are each planar. Surface 166 extends parallel to surface 160. Guidemember 156 comprises a blind hole 168 extending into surface 164. Insome embodiments, guide member 156 can be variously connected with shaft72, such as, for example, monolithic, integral connection, frictionalengagement, threaded engagement, mutual grooves, screws, adhesive,nails, barbs and/or raised element.

A collar 170 is disposed about end 104 such that an inner surface 172 ofcollar 170 engages an outer surface of end 104. Surface 172 defines apassage 174 having a cylindrical cross sectional configuration, as shownin FIG. 29. Passage 174 has a diameter that is greater than that of end104 and less than that of end 106 such that collar 170 engages ledge 108when moved relative to portion 94 in the direction shown by arrow F.Collar 170 extends along a longitudinal axis between an end 176 and anopposite end 178 comprising an end surface 180. Collar 170 comprises akeyway 182 in one portion of collar 170 and a keyway 184 in anotherportion of collar 170. End 129 of one of rods 125 disposed in holes 105extends through keyway 182 and end 129 of the other rod 125 disposed inholes 105 extends through keyway 184. Keyways 182, 184 each include aportion 186 extending parallel to the longitudinal axis defined bycollar 170 and a portion 188 extending perpendicular to the longitudinalaxis defined by collar 170. In some embodiments, portions 186 eachextend through surfaces 172, 180 without extending through an outersurface of collar 170 opposite surface 172. In some embodiments,portions 188 extend through surface 172 and the outer surface of collar170. Portions 186, 188 each have a width or diameter that is greaterthan that of end 129 such that rods 125 can move within portions 186,188, as will be discussed. In some embodiments, keyway 182 is disposedopposite keyway 184 such that keyway 182 is disposed 180 degrees fromkeyway 184. In some embodiments, portions 188 each have an arcuate endportion configured to accommodate the arcuate configuration of end 129.Collar 170 further includes spaced apart oblong openings 190 extendingperpendicular to the longitudinal axis defined by collar 170. Openings190 extend through surface 172 and the outer surface of collar 170. Insome embodiments, collar 170 includes a single opening 190. In someembodiments, opening 190 can have various shape configurations, such as,for example, oval, oblong, polygonal, irregular, uniform, non-uniform,variable and/or tapered. A pin, such as, for example, rod 125 ispositioned relative to guide member 156 such that end 127 is positionedin hole 168 and end 129 extends through slots 115, 152 for disposal inopening 190. Opening 190 has a height that is substantially equivalentto the width or diameter of end 129 such that end 129 is prevented frommoving in the direction shown by arrow E or the direction shown by arrowF within opening 190. Because shaft 72 is fixed to guide member 156,shaft 72 is axially fixed relative to collar 170. That is, as collar 170moves along axis D in the direction shown by arrow E or the directionshown by arrow F, so does shaft 72.

Push button 140 is pressed once in the direction shown by arrow F,causing ridges 150 translate within grooves 114 in the direction shownby arrow F such that actuator 118 translates within portions 92, 94 inthe direction shown by arrow F. As actuator 118 translates withinportions 92, 94 in the direction shown by arrow F, cutting element 48moves away from an end surface 45 of tube 34 in the direction shown byarrow F. When push button 140 is pressed, cutting element 84 extendsfurther from end surface 45 than does cutting element 48. In someembodiments, the distance push button 140 is moved in the directionshown by arrow F is less than the distance cutting element 48 moves awayfrom end surface 45. In some embodiments, the distance push button 140is moved in the direction shown by arrow F is equal to the distancecutting element 48 moves away from end surface 45. In some embodiments,the distance push button 140 is moved in the direction shown by arrow Fis greater than the distance cutting element 48 moves away from endsurface 45. In some embodiments, cutting element 84 extends an equaldistance from end surface 45 as cutting element 48 when push button 140is pressed. In some embodiments, cutting element 48 extends further fromend surface 45 than does cutting element 84.

As push button 140 translates within portions 92, 94 in the directionshown by arrow F, teeth 146 engage teeth 134. Due to the force appliedto portion 118 b by spring 128 and/or the angled configurations of teeth134, 146, portion 118 b rotates relative to push button 140 and/orportion 94 as teeth 134 engage teeth 146. Because ridges 150 arepositioned in grooves 114, push button 140 does not rotate relative toportion 94 as portion 118 b rotates relative to portion 94. In thatshaft 72 is fixed relative to portion 118 b, rotating portion 118 b alsorotates shaft 72 and cutting element 48 about axis D. In someembodiments, pressing push button 140 once in the direction shown byarrow F causes portion 118 b to rotate relative to push button 140 afirst amount. In some embodiments, the first amount is between about 10and about 100 degrees. In some embodiments, the first amount is betweenabout 30 and about 80 degrees. In some embodiments, the first amount isbetween about 40 and about 70 degrees. In some embodiments, the firstamount is between about 50 and about 60 degrees. In some embodiments,the first amount is about 60 degrees.

When push button 140 is pressed once in the direction shown by arrow F,portion 118 b rotates relative to portions 92, 94 such that extensions138 are aligned with grooves 114. As such, when the force used to presspush button 140 once is removed, portion 118 b moves relative toportions 92, 94 in the direction shown by arrow F. As portion 118 bmoves relative to portions 92, 94 in the direction shown by arrow F,extensions 138 move into grooves 114 and translate relative to portions92, 94 in the direction shown by arrow E. In some embodiments, theangled configuration of the top portions of extensions 138 urgesextensions 138 into grooves 114 as portion 118 b moves relative toportions 92, 94 in the direction shown by arrow E. This configurationrequires that push button 140 be pressed down to overcome the forceexerted by spring 128 to move cutting element 48 away from end surface45 in the direction shown by arrow F. Indeed, once the force used topress push button 140 down is removed, cutting element 48 moves towardend surface 45 in the direction shown by arrow E, as discussed above.This feature prevents device 32 from being locked or otherwise fixed ina position such that cutting element 48 extends beyond its initialposition relative to end surface 45.

Pressing push button 140 a second time causes portion 118 b to moverelative to portions 92, 94 in the direction shown by arrow F such thatcutting element 48 moves away from end surface 45 in the direction shownby arrow F, as described above when push button 140 is pressed once. Assuch, push button 140 may be pressed any number of times to move cuttingelement 48 away from end surface 45 in the direction shown by arrow F acorresponding number of times. Pressing push button 140 a second timealso causes portion 118 b to rotate relative to push button 140 a secondamount that is equal to the first amount, as described above, when pushbutton 140 is pressed once. As such, depending upon the degree ofrotation provided by the first amount, push button 140 may be pressed anumber of times to move cutting element 48 three hundred and sixtydegrees about axis D.

Collar 170 is positioned relative to portion 94 such that ends 129 ofthe rods 125 positioned in holes 105 are positioned in portions 188 ofkeyways 182, 184. This configuration prevents collar 170 fromtranslating relative to portion 94 in the direction shown by arrow F.Collar 170 is rotated relative to portion 94 about axis D in a firstdirection, such as, for example, clockwise or counterclockwise, to moveends 129 of the rods 125 positioned in holes 105 from portions 188 ofkeyways 182, 184 and into portions 186 of keyways 182, 184, thusallowing collar 170 to translate relative to portion 94 in the directionshown by arrow E. Collar 170 is translated along axis D in the directionshown by arrow E such that guide member 156 also translates in thedirection shown by arrow E. As guide member 156 also translates in thedirection shown by arrow E, cutting member 84 translates in thedirection shown by arrow E. The maximum distance cutting member 84 cantranslate along axis D in the direction shown by arrow E is limited bythe length of slot 152. In some embodiments, slot 152 has a length thatpermits cutting member 84 to be translated along axis D in the directionshown by arrow E until cutting member 84 is disposed entirely withinpassageway 42.

In assembly, operation and use, system 30 is employed with a surgicalprocedure, such as, for a treatment of a hypertrophied ligamentumflavum. It is contemplated that one or all of the components of system30 can be delivered or implanted as a pre-assembled device or can beassembled in situ. System 30 may be completely or partially revised,removed or replaced. It is envisioned that system 30 may also be used totreat other affected portions of the patient, such as, for example, acalcaneus bone, bones of the feet or hands, bones of the spine, bones ofthe arms and legs, etc.

In use, to treat a hypertrophied ligamentum flavum, a medicalpractitioner obtains access to a surgical site including in anyappropriate manner, such as through the skin, or through an incision andretraction of tissues. In one embodiment, a drill is employed to removebone tissue to provide access to a repair site. It is envisioned thatsystem 30 can be used in any existing surgical method or techniqueincluding open surgery, mini-open surgery, minimally invasive surgeryand percutaneous surgical implantation, whereby the fractured or injuredbone is accessed through a mini-incision or sleeve that provides aprotected passageway to the area. Once access to the surgical site isobtained, the particular surgical procedure can be performed fortreating the injury or disorder. The configuration and dimension ofsystem 30 is determined according to the configuration, dimension andlocation of a selected section of nerves and the requirements of aparticular application.

An incision is made in the body of a patient and a cutting instrument(not shown) creates a surgical pathway for implantation of components ofsystem 30. This may include the use of a cannula or other device. Apreparation instrument (not shown) can be employed to prepare tissuesurfaces, as well as for aspiration and irrigation of a surgical regionaccording to the requirements of a particular surgical application.

Device 32 is inserted into the surgical site, such as, for exampleadjacent a ligamentum flavum. In some embodiments, device 32 ispositioned adjacent the ligamentum flavum such that cutting element 84engages the ligamentum flavum and cutting element 48 is spaced apartfrom the ligamentum flavum. In some embodiments, engaging cuttingelement 84 with the ligamentum flavum comprises positioning cuttingelement 84 such that cutting element 84 penetrates the ligamentumflavum. In some embodiments, engaging cutting element 84 with theligamentum flavum comprises positioning cutting element 84 such that aportion of the ligamentum flavum is positioned within a hook portion ofthe ligamentum flavum.

Push button 140 is pressed once, as described above, to move cuttingelement 48 away from end surface 45 in the direction shown by arrow F.As cutting element 48 moves away from end surface 45 in the directionshown by arrow F, cutting element 48 penetrates the ligamentum flavum.As discussed above, cutting element 48 also rotates about axis D whenpush button 140 is pressed. As such, cutting element 48 rotates aboutaxis D as cutting element 48 moves away from end surface 45 in thedirection shown by arrow F such that cutting element 48 penetrates theligamentum flavum as cutting element 48 rotates about axis D andsimultaneously penetrates the ligamentum flavum as cutting element 48moves away from end surface 45 in the direction shown by arrow F. Whenpush button 140 is released, portion 118 b moves relative to portions92, 94 in the direction shown by arrow E such that cutting element 48translates in the direction shown by arrow E. As cutting element 48translates in the direction shown by arrow E, cutting element 48 cutsthrough the ligamentum flavum. Push button 140 may be pressed a selectednumber of times to rotate cutting element 48 a selected amount aboutaxis D.

In some embodiments, cutting element 48 is rotated three hundred andsixty degrees about axis D such that cutting element 48 cuts asubstantially circular and/or disc shaped portion of the ligamentumflavum. However, it should be understood that the shape, size, etc. ofthe portion of the ligamentum flavum that is to be removed from theremaining portion of the ligamentum flavum may have any configurationselected by the medical practitioner, and hence need not besubstantially circular and/or disc shaped. For clarity, the portion ofthe ligamentum flavum that is removed from the remaining portion of theligamentum flavum will be referred to as the substantially circularand/or disc shaped portion of the ligamentum flavum. In someembodiments, the disc shaped portion of the ligamentum flavum isremovable from a remaining portion of the ligamentum flavum. That is,there is no tissue or otherwise connecting the disc shaped portion ofthe ligamentum flavum with the remaining portion of the ligamentumflavum that may prevent the disc shaped portion of the ligamentum flavumfrom being removed from the remaining portion of the ligamentum flavum.In some embodiments, cutting element 48 is rotated less than threehundred and sixty degrees about axis D. In some embodiments, cuttingelement 48 is rotated more than three hundred and sixty degrees aboutaxis D to ensure that the disc shaped portion of the ligamentum flavumis removable from a remaining portion of the ligamentum flavum. Asdiscussed above, the number of times push button 140 needs to be pressedin order to rotate cutting element 48 about axis D the selected amountis dependent upon the amount pressing push button 140 once rotatescutting element 48 about axis D. In some embodiments, a medicalpractitioner may press push button 140 between 5 and 50 times to rotatecutting element 48 three hundred and sixty degrees about axis D.

Collar 170 is positioned relative to portion 94 such that ends 129 ofthe rods 125 positioned in holes 105 are positioned in portions 188 ofkeyways 182, 184. This configuration prevents collar 170 fromtranslating relative to portion 94 in the direction shown by arrow F.Collar 170 is rotated relative to portion 94 about axis D in a firstdirection, such as, for example, clockwise or counterclockwise, to moveends 129 of the rods 125 positioned in holes 105 from portions 188 ofkeyways 182, 184 and into portions 186 of keyways 182, 184, thusallowing collar 170 to translate relative to portion 94 in the directionshown by arrow E. Collar 170 is translated along axis D in the directionshown by arrow E such that guide member 156 also translates in thedirection shown by arrow E. As guide member 156 translates in thedirection shown by arrow E, cutting member 84 translates in thedirection shown by arrow E such that cutting element 84 pulls the discshaped portion of the ligamentum flavum away from the remaining portionof the ligamentum flavum.

Upon completion of the surgical procedure, device 32 is removed from thesurgical site. It is envisioned that the use of microsurgical and imageguided technologies may be employed to access, view and repair spinaldeterioration or damage, with the aid of device 32. It is contemplatedthat a surgical procedure may employ other instruments that can bemounted with device 32, such as, for example, nerve root retractors,tissue retractors, forceps, cutter, drills, scrapers, reamers, rongeurs,taps, cauterization instruments, irrigation and/or aspirationinstruments, illumination instruments, inserter instruments and/orseparators, such as, for example, one or more burrs. Device 32 may beemployed for performing spinal surgeries, such as, for example,laminectomy, discectomy, fusion, laminotomy, nerve root retraction,foramenotomy, facetectomy, decompression, spinal nucleus or discreplacement and procedures using bone graft and implantable prostheticsincluding plates, rods, and bone engaging fasteners.

It will be understood that various modifications may be made to theembodiments disclosed herein. Therefore, the above description shouldnot be construed as limiting, but merely as exemplification of thevarious embodiments. Those skilled in the art will envision othermodifications within the scope and spirit of the claims appended hereto.The embodiments above can also be modified so that some features of oneembodiment are used with the features of another embodiment. One skilledin the art may find variations of these preferred embodiments, which,nevertheless, fall within the spirit of the present invention, whosescope is defined by the claims set forth below.

I claim:
 1. A surgical method comprising: providing a cutting devicecomprising: an outer tube extending along a longitudinal axis between aproximal end and a distal end, the outer tube comprising an innersurface defining a passageway; an inner tube movably disposed in thepassageway such that a distal end of the inner tube extends beyond thedistal end of the outer tube, the distal end of the inner tubecomprising a first cutting element comprising a plurality of tines in atine arrangement, and an inner surface of the inner tube defining alumen; a shaft slidably disposed in the lumen, the shaft comprising adistal end including a second cutting element comprising a stylet thatprotrudes distally from a center of the tine arrangement; and adeployment mechanism coupled to the proximal end of the outer tube andcomprising a body, a push button disposed within the body, the innertube being axially fixed relative to the push button; creating an accesspath to a surgical site and positioning the distal end of the outer tubeat or adjacent the surgical site; and moving the push button distallyrelative to the body to actuate movement of the first cutting elementfrom a first orientation having a first radial position relative to theouter tube and the surgical site to a second orientation having a secondradial position relative to the outer tube and the surgical site that isdifferent than the first radial position.
 2. The method of claim 1,wherein the deployment mechanism further comprises a collar disposedabout the body, the shaft including the second cutting element beingaxially fixed relative to the collar; and further comprising moving thecollar relative to the body along the longitudinal axis such that theshaft including the second cutting element moves between a firstconfiguration in which the second cutting element is disposed within thelumen and a second configuration in which the second cutting element ispositioned outside of the lumen at or adjacent the surgical site.
 3. Themethod of claim 2, further comprising moving the second cutting elementin the second configuration such that the second cutting element pullson a ligamentum flavum to increase potential epidural space.
 4. Themethod of claim 3, further comprising locking the shaft in the secondconfiguration by rotating the collar about the body.
 5. The method ofclaim 1, wherein the deployment mechanism further comprises an actuatormoveably disposed within the body, and further comprises a springpositioned between the body and a distal end of the actuator, theactuator comprises teeth on a proximal end thereof, and the push buttoncomprises a distal end comprising teeth, the teeth on the push buttonbeing configured to engage the teeth on the proximal end of theactuator, and the inner tube being fixed relative to the actuator. 6.The method of claim 5, further comprising moving the push buttondistally relative to the body to cause the teeth on the push button toengage the teeth on the actuator such that the actuator rotates relativeto the push button about the longitudinal axis; and wherein the innertube rotates relative to the outer tube about the longitudinal axis asthe actuator rotates relative to the push button about the longitudinalaxis.
 7. The method of claim 1, wherein the deployment mechanism furthercomprises an actuator moveably disposed within the body, and furthercomprises a spring positioned between the body and a distal end of theactuator, the spring biasing the actuator toward the push button suchthat moving the push button distally relative to the body causes teethon the push button to engage teeth on the actuator such that theactuator rotates relative to the push button about the longitudinalaxis; and wherein the inner tube rotates relative to the outer tubeabout the longitudinal axis as the actuator rotates relative to the pushbutton about the longitudinal axis.
 8. The method of claim 1, whereinthe deployment mechanism further comprises an actuator moveably disposedwithin the body; and further comprising moving the push button relativeto the body between a first configuration in which projections on anouter surface of the actuator are spaced apart from grooves in an innersurface of the body and the actuator is prevented from moving proximallyrelative to the body, and a second configuration in which theprojections are disposed in the grooves and the actuator movesproximally relative to the body.
 9. The method of claim 1, wherein aproximal end of the shaft is coupled to a guide member slidablypositioned within the push button, the guide member comprising a pinextending through a slot in the push button and a slot in the body, thepin being axially fixed relative to the collar.
 10. A surgical methodcomprising: providing a cutting device comprising: an outer tubeextending along a longitudinal axis between a proximal end and a distalend, the outer tube comprising an inner surface defining a passageway;an inner tube movably disposed in the passageway such that a distal endof the inner tube extends beyond the distal end of the outer tube, thedistal end of the inner tube comprising a first cutting elementincluding a plurality of tines in a tine arrangement, and an innersurface of the inner tube defining a lumen; a shaft slidably disposed inthe lumen, the shaft comprising a distal end including a second cuttingelement comprising a stylet that protrudes distally from a center of thetine arrangement; and a deployment mechanism coupled to the proximal endof the outer tube and comprising a body, a push button disposed withinthe body, and a collar disposed about the body, the shaft including thesecond cutting element being axially fixed relative to the collar, andthe inner tube being axially fixed relative to the push button; creatingan access path to a surgical site and positioning the distal end of theouter tube at or adjacent the surgical site; moving the push buttondistally relative to the body to actuate movement of the first cuttingelement from a first orientation having a first radial position relativeto the outer tube and the surgical site to a second orientation having asecond radial position relative to the outer tube and the surgical sitethat is different than the first radial position; moving the collarrelative to the body along the longitudinal axis such that the shaftincluding the second cutting element moves between a first configurationin which the second cutting element is disposed within the lumen and asecond configuration in which the second cutting element is positionedoutside of the lumen at or adjacent the surgical site; and locking theshaft in the second configuration by rotating the collar about the body.11. The method of claim 10, further comprising moving the second cuttingelement in the second configuration such that the second cutting elementpulls on a ligamentum flavum to increase potential epidural space. 12.The method of claim 10, wherein the deployment mechanism furthercomprises an actuator moveably disposed within the body, and furthercomprises a spring positioned between the body and a distal end of theactuator, the actuator comprises teeth on a proximal end thereof, andthe push button comprises a distal end comprising teeth, the teeth onthe push button being configured to engage the teeth on the proximal endof the actuator, and the inner tube being fixed relative to theactuator.
 13. The method of claim 12, further comprising moving the pushbutton distally relative to the body to cause the teeth on the pushbutton to engage the teeth on the actuator such that the actuatorrotates relative to the push button about the longitudinal axis; andwherein the inner tube rotates relative to the outer tube about thelongitudinal axis as the actuator rotates relative to the push buttonabout the longitudinal axis.
 14. The method of claim 10, wherein thedeployment mechanism further comprises an actuator moveably disposedwithin the body, and further comprises a spring positioned between thebody and a distal end of the actuator, the spring biasing the actuatortoward the push button such that moving the push button distallyrelative to the body causes teeth on the push button to engage teeth onthe actuator such that the actuator rotates relative to the push buttonabout the longitudinal axis; and wherein the inner tube rotates relativeto the outer tube about the longitudinal axis as the actuator rotatesrelative to the push button about the longitudinal axis.
 15. The methodof claim 10, wherein the deployment mechanism further comprises anactuator moveably disposed within the body; and further comprisingmoving the push button relative to the body between a firstconfiguration in which projections on an outer surface of the actuatorare spaced apart from grooves in an inner surface of the body and theactuator is prevented from moving proximally relative to the body, and asecond configuration in which the projections are disposed in thegrooves and the actuator moves proximally relative to the body.
 16. Themethod of claim 10, wherein a proximal end of the shaft is coupled to aguide member slidably positioned within the push button, the guidemember comprising a pin extending through a slot in the push button anda slot in the body, the pin being axially fixed relative to the collar.17. A surgical method comprising: providing a cutting device comprising:an outer tube extending along a longitudinal axis between a proximal endand a distal end, the outer tube comprising an inner surface defining apassageway; an inner tube movably disposed in the passageway such that adistal end of the inner tube extends beyond the distal end of the outertube, the distal end of the inner tube comprising a first cuttingelement, and an inner surface of the inner tube defining a lumen; ashaft slidably disposed in the lumen, the shaft comprising a distal endincluding a second cutting element; and a deployment mechanism coupledto the proximal end of the outer tube and comprising a body, a pushbutton disposed within the body, a collar disposed about the body, andan actuator moveably disposed within the body, the shaft including thesecond cutting element being axially fixed relative to the collar, andthe inner tube being axially fixed relative to the push button, the pushbutton comprising a distal end comprising teeth, the teeth beingconfigured to engage teeth on a proximal end of the actuator, the innertube being fixed relative to the actuator; creating an access path to asurgical site and positioning the distal end of the outer tube at oradjacent the surgical site; moving the push button distally relative tothe body to both actuate rotation of the actuator and the inner tubefixed relative thereto via the interaction of the teeth of the pushbutton with the teeth of the actuator, and actuate movement of the firstcutting element from a first orientation having a first radial positionrelative to the outer tube and the surgical site to a second orientationhaving a second radial position relative to the outer tube and thesurgical site that is different than the first radial position; andmoving the collar relative to the body along the longitudinal axis suchthat the shaft including the second cutting element moves between afirst configuration in which the second cutting element is disposedwithin the lumen and a second configuration in which the second cuttingelement is positioned outside of the lumen at or adjacent the surgicalsite.
 18. The method of claim 17, wherein the first cutting elementcomprises a plurality of tines in a tine arrangement.
 19. The method ofclaim 17, further comprising moving the second cutting element in thesecond configuration such that the second cutting element pulls on aligamentum flavum to increase potential epidural space.
 20. The methodof claim 17, wherein the deployment mechanism further comprises aspring, and the spring biases the actuator toward the push button.